In a common power take-off device, the input shaft is connected to the first and, selectively, the second shaft by two sleeves: a first sleeve is coaxial with the first shaft and movable axially between an operating position, in which the first shaft is connected to the input shaft to rotate at the first speed, and an idle position corresponding to an idle position of the first shaft; and the second sleeve is coaxial with the second shaft and movable axially between two operating positions, in which the second shaft is connected to the input shaft to rotate at the second and third speed respectively, and an intermediate idle position corresponding to an idle position of the second shaft.
Each sleeve can only be set to the respective operating position when the other sleeve is idle, and both sleeves are user-activated by means of respective control levers installed in the operator cab and connected to the respective sleeves by respective drives.
Though efficient and widely used, the above device has several drawbacks, mainly due to it being extremely complicated mechanically, and therefore complicated to produce and operate.